The present invention relates to pipe bending machines and more particularly concerns such machines that are able to make either right-hand or left-hand bends.
In the use of rotary bending machines to make a series of bends in a pipe, the direction of the several bends must be so chosen that when making the second or subsequent bend in a given length of pipe, the previously bent pipe portion, which extends forwardly and at an angle because of the prior bend, does not interfere with the bending head itself. Thus, the direction of each bend is often selected so that the previously bent pipe portion will move away from rather than toward the bend head during the bending operation. In any event, it must not move so as to interfere with or engage the bend head or other parts of the machine. Different required configurations of pipe may require different directions of bend, and thus it has been the practice to change dies or select other bend dies when changing from a right-hand bend to a left-hand bend.
U.S. Pat. No. 3,017,917 to Streit shows a machine adapted for right-hand and left-hand bending without tooling changeover. According to this patent, the entire bend head, including its support and driving mechanism, must be rotated through a full 180.degree., but no carriage or automatic pipe handling apparatus is employed.
In a co-pending application of Homer L. Eaton, Ser. No. 887,725 filed Mar. 17, 1978, now U.S. Pat. No. 4,201,073 and assigned to the assignee of the present application, there is described an automatic rotary bending machine capable of making right-hand and left-hand bends in which first and second sets of rotary bend dies are mounted on a common horizontal bend axis and a pipe handling carriage is mounted for motion along a horizontal track to advance a pipe toward the bend head and to position the pipe rotationally about the pipe axis. This machine is arranged to provide right-hand or left-hand bending by supporting the track at its rear for pivotal motion about a vertical axis and detachably connecting the track at its forward end to the bend head support so that it may be connected in alignment with either one of the two sets of bend dies. To change the set up of this machine of the co-pending application of Homer Eaton from right-hand to left-hand bending requires disconnecting the track from the bend head support, pivoting the track at its rear support, also pivotally shiffting the bend head support, and then reconnecting the forward end of the track to the bend head support. This operation requires several steps and is time consuming.
Accordingly, it is an object of the present invention to provide a bending machine for making either right-hand or left-hand bends which avoids or eliminates above-mentioned problems.